//- 设置根元素fontSize~
(function (doc, win) {
    var _root = doc.documentElement,
        resizeEvent = 'orientationchange' in window ? 'orientationchange' : 'resize',
        resizeCallback = function () {
            var clientWidth = _root.clientWidth>768?768:_root.clientWidth,
                fontSize = 0;
            if (!clientWidth) return;
           fontSize = clientWidth / 10.8;
            /* else {
                 fontSize = 100 * (640 / 320);
             }*/
						 fontSize=fontSize
            _root.style.fontSize = fontSize + 'px';
            // alert(fontSize)
            // _root.style.fontSize = 100 + 'px';
        };
   if (!doc.addEventListener) return;
    win.addEventListener(resizeEvent, resizeCallback, false);
  //  document.addEventLstener('DOMContentLoaded', resizeCallback, false);
    doc.addEventListener("DOMContentLoaded", function(event) {
        resizeCallback()
    });
})(document, window);